Update key_file generator script

- Prevent overwrite of key file if it already exists
- Option to force key file overwrite if required

InvenTree/key.py

@@ -3,8 +3,11 @@
 import random
 import string
 import os
+import sys
+import argparse
 
-fn = 'secret_key.txt'
+KEY_FN = 'secret_key.txt'
+KEY_DIR = os.path.dirname(os.path.realpath(__file__))
 
 
 def generate_key():
@@ -14,11 +17,29 @@ def generate_key():
 
 
 if __name__ == '__main__':
+    
+    parser = argparse.ArgumentParser(description='Generate Django SECRET_KEY file')
+    parser.add_argument('--output', help='Specify key file path', default=None)
+    parser.add_argument('--force', '-f', help='Override key file (if it exists)', action='store_true')
+    parser.add_argument('--dummy', '-d', help='Dummy run (display key only', action='store_true')
+    
+    args = parser.parse_args()
 
-    # Ensure key file is placed in same directory as this script
-    path = os.path.dirname(os.path.realpath(__file__))
-    key_file = os.path.join(path, fn)
+    if args.output:
+        key_filename = args.output
+    else:
+        key_filename = os.path.join(KEY_DIR, KEY_FN)
 
-    with open(key_file, 'w') as kf:
-        kf.write(generate_key())
-        print('Generated SECRET_KEY to {f}'.format(f=key_file))
+    key_data = generate_key()
+
+    if args.dummy:
+        print('SECRET_KEY: {k}'.format(k=key_data))
+        sys.exit(0)
+
+    if not args.force and os.path.exists(key_filename):
+        print("Key file already exists - '{f}'".format(f=key_filename))
+        sys.exit(0)
+
+    with open(key_filename, 'w') as key_file:
+        print("Generating SECRET_KEY file - '{f}'".format(f=key_filename))
+        key_file.write(key_data)